1. Field of Invention
The present invention relates to a technique for real time air measurement in wet concrete; more particularly related to a technique for real time air measurement in wet concrete in order to control the amount of air in a mixture of concrete.
2. Description of Related Art
The measurement of density in process industries is important in a wide range of applications, including: chemical processing, refining, food processing, mining, dredging, and waste water processing. In many applications, the current technology of choice is a Nuclear Density meter. Due to the use of an active nuclear source (gamma ray) in these meters, these devices require a certain degree of regulatory oversight, including training, specialized personnel, and handling/disposal procedures etc. Consequently, there is a push in many industries to replace Nuclear Density Measurement with Non-Nuclear devices.
The assignee of the present application has developed a platform technology, sold under the product name, SONARtrac™, that measures the speed at which sound travels within a fluid or slurry (e.g., the speed at which compressional waves propagate through a fluid). The technique has proven to provide a very robust measurement and has been applied to a range of applications in industrial processing, particularly where the entrained air and/or gas measurements are of interest.
While the measurement of the speed of sound (SOS) in a fluid can be used to give a measure of the constituents of a flow (for example oil-water in an oil production application), it's direct use for density measurement is limited unless there is a priori knowledge of the density of the component constituents (or “phases”) of the process flow stream.